1. Field of the Invention
The invention relates to a torque-switched clutch between an input shaft and an output shaft, which transfers into a release position from a positive-locking connection when a limiting torque is reached, the clutch comprising at least one positive-locking element, which is connected to one shaft and interacts with a positive-locking receiver of the other shaft, the positive-locking element being movable against a force out of a coupling position into a release position in a non-destructive manner.
2. Description of the Prior Art
Torque-switched clutches of this kind are known in the form of friction-locking or positive-locking overload clutches. From a certain limiting torque onwards, the friction-locking overload clutches slip, as a result of which the fixed connection between the coupled shafts is interrupted and a further rise in the torque is prevented. In the positive-locking designs, the torque is transmitted by interengaging parts of the clutch halves. When the limiting torque is reached, the clutch disengages. A torque-switched clutch of this kind is known, for example, from German Published Patent Application No. 2,720,549, in which a description is given of a torque-regulating device in which the coupling position is defined by balls associated with the input shaft and the output shaft, these balls being brought into engagement with one another. When the limiting torque is reached, the clutch-forming balls associated with one of the shafts move back, the movement taking the form of a relative axial displacement, such that the balls associated with the other shaft slide over these deflected balls. The receivers located between the individual balls of one shaft, which ensure positive locking in the coupling position, have the effect of a continuous engagement and disengagement, in the position in which the limiting torque is exceeded, as soon as the balls of one of the shafts have slid over the balls of the other shaft, which have moved back against a spring force. One disadvantage of this and the other known clutch designs is that the connection is not continuously interrupted after the limiting torque has been reached. In the case of the friction-locking slipping clutch, the slipping torque acts continuously. In the case of the positive-locking designs, as already described, there is continuous engagement and disengagement. As a result, high friction and severe wear occur in the clutch.